Dairy Cow Manure Visual
Evaluation for Ration Adjustment

Evaluating a dairy cow's output can provide you with valuable input
for optimizing feed efficiency and animal health. Her manure can
indicate the condition of her rumen and intestine to help identify
potential problems.

Regularly taking just a few minutes to look at your cows' manure
can unearth clues about whether they are eating properly. Manure
texture, colour and content can provide key information.

Texture

Manure from lactating cows normally has a porridge-like consistency
and forms a dome-shaped pile of 2.5 to five centimetres high when
freshly dropped. Whether loose or firm, texture should be consistent
throughout a group of cows receiving a similar ration. If you observe
discrepancies, this could mean some cows are able to sort their
feed.

Manure consistency can range from very liquid like pea soup to
very firm horse-like droppings. Linked to water and fibre content,
manure consistency is influenced by factors such as feed moisture
content, feed type and passage rate (the amount of time feed remains
in the animal).

Cows with liquid or runny manure may have too much protein, high
levels of rumen degradable protein or starch in their rations. A
lack of effective fibre, excess salt or mineral imbalance could
also cause it.

When extensive hind gut fermentation of carbohydrates takes place,
increased acid production can lead to runny manure. In this case,
fine gas bubbles can give the manure a foamy appearance. Investigate
it promptly since it may be a sign of rumen acidosis-when rumen
pH becomes too acidic.

If the manure consistency is thick or even firm, like horse droppings,
it could indicate too little protein or starch in the ration or
a very fibre-rich ration. Dehydration can also lead to firm manure.

Colour

Factors such as feed type, passage rate, health disorders and so
forth can influence manure colour.

Depending on the forage type a cow consumes, its manure colour
can vary from dark green from fresh forages and pasture to brown
from dry hay. A total mixed ration with a substantial concentrate
level can turn manure a yellow-olive colour.

A group of cows getting a similar ration should have a uniform
manure colour. If one animal's manure colour significantly differs
from the rest of the group, investigate further.

Content

The most interesting aspect of manure evaluation from both a nutritionist
and producer perspective is content. What ends up in the manure
is technically considered indigestible material.

Sometimes though, because of various factors, a cow might not digest
feed ingredients that she could have digested. Potentially digestible
material that ends up in manure might suggest problems with rumen
function, feed processing or feeding management.

When undigested feed is not converted to milk, your production
cost increases. Grain should not show up in the manure-especially
when grain prices are high.

Rumination and digestion by microbes in the rumen break down fibre
and feed particle size. When a cow does not eat enough fibre to
maintain rumination and rumen function, digestibility is reduced.
Feed can pass out of her rumen more quickly and in larger particles
than it should.

High-producing cows eat more feed and rumen contents pass through
their digestive tracts more quickly. More undigested feed may show
up in their manure. However, you can manage the ration to minimize
this.

Managing concentrate and forage particle size can greatly improve
feed overall digestibility. A particle separator can be useful to
sift the ration and evaluate whether the ration has optimal particle
size.

Under optimal conditions, the rumen ferments most of the feed,
and less passes to the small intestine for digestion or the cecum
and large intestine, together known as the hindgut, for fermentation.
When the rumen is working poorly, more potentially fermentable feed
escapes rumen fermentation and the amount fermented in the hindgut
can increase.

Increased hindgut fermentation generates more gas and acid production
that can change manure's consistency and appearance. The hindgut
is not as buffered and cannot handle the acidity as well as the
rumen can. Excessive hindgut fermentation can cause diarrhea and
foamy manure.

An effective way to evaluate manure content is washing it down
with water through a screen or a kitchen sieve (see sidebar). This
simple process lets you quickly find out whether feed processing
and digestion is optimal.

What you might see and learn could surprise you. Your herd nutritionist
can help you adjust the ration if needed to ensure a healthy, efficient
and productive herd.

SIDEBAR: Washing manure

The manure washing procedure is quite simple. Collect a representative
manure sample in a container and thoroughly mix it. Place a cup
of the mix in the sieve and wash it with a stream of water through
the screen to remove digested material.

Once the water runs clear, check the remaining material. Look for
feed particles, pieces of grain containing starch or whole hard
grains. Sometimes, careful observation is required since grain hulls
can be confused with undigested grain. Make sure by opening hulls
to see if starch is still present.

Evaluate fibre particle size as well. Ideally, few feed particles
in the manure should be more than 1.25 cm, or half an inch long.

There should be little, if any, recognizable feed present. Presence
of long particles or undigested material can indicate cows are not
ruminating properly, are sorting feed, receiving too much grain
in one meal or lacking effective, or long, fibre.

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